M37212 Mitsubishi, M37212 Datasheet - Page 74

• Manufacturer Part Number: M37212
• Description: SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER for VOLTAGE SYNTHESIZER
• Manufacturer: Mitsubishi

8.13 CLOCK GENERATING CIRCUIT
The built-in clock generating circuit is shown in Figure 8.13.3. When
the STP instruction is executed, the internal clock
At the same time, timers 3 and 4 are connected by hardware and
“FF
as the timer 3 count source (set bit 0 of the timer mode register 2 to
“0” before the execution of the STP instruction). Moreover, set the
timer 3 and timer 4 interrupt enable bits to disabled (“0”) before ex-
ecution of the STP instruction). The oscillator restarts when external
interrupt is accepted. However, the internal clock
until timer 4 overflows, allowing time for oscillation stabilization when
a ceramic resonator or a quartz-crystal oscillator is used.
When the WIT instruction is executed, the internal clock
the HIGH but the oscillator continues running. This wait state is re-
leased when an interrupt is accepted (See note). Since the oscillator
does not stop, the next instruction can be executed at once.
When returning from the stop or the wait state, to accept an interrupt,
set the corresponding interrupt enable bit to “1” before executing the
STP or the WIT instructions.
Note: In the wait mode, the following interrupts are invalid.
A circuit example using a ceramic resonator (or a quartz-crystal os-
cillator) is shown in Figure 8.13.1. Use the circuit constants in accor-
dance with the resonator manufacture’s recommended values. A cir-
cuit example with external clock input is shown in Figure 8.13.2. In-
put the clock to the X
Fig. 8.13.3 Clock Generating Circuit Block Diagram
74
16
” is set in timer 3 and “07
• V
• OSD interrupt
• All timers interrupts using TIM2 and TIM3 pins input as count source
• All timers interrupts using f(X
• All timers interrupts using f(X
• f(X
• Multi-master I
SYNC
T 3 4 M :
T i m e r 3 4 m o d e r e g i s t e r
IN
)/4096 interrupt
S e l e c t i o n g a t e :
interrupt
C o n n e c t e d t o b l a c k
s i d e a t r e s e t .
2
C-BUS interface interrupt
IN
pin, and open the X
I n t e r r u p t r e q u e s t
I n t e r r u p t d i s a b l e
16
” is set in the timer 4. Select f(X
IN
IN
)/2 as count source
)/4092 as count source
X
I N
f l a g I
OUT
M37212M4/M8–XXXSP, M37212M6–XXXSP/FP
X
R e s e t
O U T
pin.
S T P i n s t r u c t i o n
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER for VOLTAGE SYNTHESIZER
keeps its HIGH
stops at HIGH.
1 / 2
stops in
IN
)/16
1 / 8
S
R
Fig. 8.13.1 Ceramic Resonator Circuit Example
Fig. 8.13.2 External Clock Input Circuit Example
T 3 4 M 0
Q
External oscillation circuit
X
W I T
i n s t r u c t i o n
IN
Microcomputer
T 3 4 M 2
with ON-SCREEN DISPLAY CONTROLLER
X
S
R
IN
MITSUBISHI MICROCOMPUTERS
Microcomputer
C
IN
Q
T i m e r 3
M37212EFSP/FP
Vcc
Vss
Q
X
OUT
C
R
S
OUT
T i m e r 4
I n t e r n a l c l o c k
S T P
i n s t r u c t i o n
R e s e t
Rev. 1.0